Some of the major technological applications for unsaturated aliphatic diacid anhydrides, particularly maleic anhydride, grafted polyolefins is to form adhesive olefin polymers, compatibilized olefin polymers, and reversible crosslinked base resins. Maleic anhydride grafted polyolefins also find utility as adhesion promoters because of their compatibility with polar copolymers such as ethylene/ethyl acrylate copolymers, ethylene/vinyl acetate copolymers, polyesters, and polyamides because of the nature of the anhydride group.
Various techniques have been proposed for preparing maleic anhydride grafted polyolefins. Grafting techniques require an initial preblending, soaking, or spraying of the maleic anhydride onto the polyolefin. This still requires hot melt processing of the mixture after the soak or spray. Batch solution grafting has also been demonstrated. In all of these techniques, the objective is to achieve a high level of grafting without substantial increases in molecular weight (measured as substantial decreases in melt index). Those skilled in the art are constantly striving to optimize the anhydride level with minimal increases in molecular weight, and to prepare the anhydride and resin in a more efficient manner for extrusion.